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Overview

The input validation module provides Kotlin extension functions for validating user input, specifically email addresses and passwords. These validators are used throughout the authentication flow. File Location: com.demodogo.ev_sum_2.domain.validators.Validators

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Email Validation

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isBasicEmailValid()

Extension function that validates email format with basic checks. 
fun String.isBasicEmailValid(): Boolean =
    contains("@") && contains(".") && emailDomain.isNotBlank()
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this
String
required
The email string to validate
Returns: Boolean - true if the email meets basic validation criteria

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Validation Rules

The email is considered valid if it:
  • Contains the ”@” symbol
  • Contains at least one ”.” character
  • Has a non-blank domain after the ”@” symbol

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emailDomain Property

Helper property that extracts the domain portion of an email: 
val String.emailDomain: String
    get() = substringAfter("@", missingDelimiterValue = "")
Returns an empty string if no ”@” symbol is found.

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Usage Examples

// Valid emails
"[email protected]".isBasicEmailValid()  // true
"[email protected]".isBasicEmailValid()     // true
"[email protected]".isBasicEmailValid()  // true

// Invalid emails
"invalid".isBasicEmailValid()           // false (no @)
"no@domain".isBasicEmailValid()         // false (no .)
"@nodomain.com".isBasicEmailValid()     // false (blank domain)
"user@".isBasicEmailValid()             // false (blank domain)

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Integration with UI

Used in authentication screens for email validation: 
@Composable
fun LoginScreen() {
    var email by remember { mutableStateOf("") }
    
    Button(
        onClick = {
            val cleanEmail = email.trim()
            when {
                cleanEmail.isBlank() -> {
                    // Show error: "Completa tu email"
                }
                !cleanEmail.isBasicEmailValid() -> {
                    // Show error: "Email inválido"
                }
                else -> {
                    // Proceed with login
                }
            }
        }
    ) {
        Text("Login")
    }
}

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Password Validation

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isValidPassword()

Extension function that validates password strength requirements. 
fun String.isValidPassword(): Boolean =
    length >= 6 && any { it.isLetter() } && any { it.isDigit() } && !contains(" ")
​
this
String
required
The password string to validate
Returns: Boolean - true if the password meets all strength requirements

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Validation Rules

The password is considered valid if it:
  • Is at least 6 characters long
  • Contains at least one letter (a-z, A-Z)
  • Contains at least one digit (0-9)
  • Does not contain any spaces

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Usage Examples

// Valid passwords
"pass123".isValidPassword()      // true
"Abc123".isValidPassword()       // true
"a1b2c3".isValidPassword()       // true

// Invalid passwords
"12345".isValidPassword()        // false (no letters)
"abcdef".isValidPassword()       // false (no digits)
"abc12".isValidPassword()        // false (too short)
"pass 123".isValidPassword()     // false (contains space)

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Integration with UI

Used in registration screen for password validation: 
@Composable
fun RegisterScreen() {
    var password by remember { mutableStateOf("") }
    
    Button(
        onClick = {
            when {
                password.isBlank() -> {
                    // Show error: "Completa tu contraseña"
                }
                !password.isValidPassword() -> {
                    // Show error: "La contraseña debe tener al menos 6 caracteres, 
                    //             1 letra y 1 número"
                }
                else -> {
                    // Proceed with registration
                }
            }
        }
    ) {
        Text("Register")
    }
}

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Validation Messages

Common error messages used with these validators:
  • Blank email: “Completa tu email”
  • Invalid format: “Email inválido (ej: [email protected])”
  • Blank password: “Completa tu contraseña”
  • Invalid format: “La contraseña debe tener al menos 6 caracteres, 1 letra y 1 número”

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Testing

These validators are designed to be easily testable since they’re pure functions: 
@Test
fun testEmailValidation() {
    assertTrue("[email protected]".isBasicEmailValid())
    assertFalse("invalid".isBasicEmailValid())
    assertFalse("@nodomain".isBasicEmailValid())
}

@Test
fun testPasswordValidation() {
    assertTrue("pass123".isValidPassword())
    assertFalse("12345".isValidPassword())
    assertFalse("short1".isValidPassword())
    assertFalse("pass 123".isValidPassword())
}

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Comparison with Speech Normalization

While speech normalization converts spoken words to typed format, input validation ensures the final result meets security and format requirements:
Converts spoken input to typed format:
normalizeEmailFromSpeech("admin arroba test punto cl")
// Returns: "[email protected]"

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Source Code

View the complete implementation in the repository: app/src/main/java/com/demodogo/ev_sum_2/domain/validators/Validators.kt

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